Test Observable.takeWhile;

tests/observable.lua

@@ -173,4 +173,5 @@ describe('Observable', function()
   dofile('tests/skipWhile.lua')
   dofile('tests/take.lua')
   dofile('tests/takeUntil.lua')
+  dofile('tests/takeWhile.lua')
 end)

tests/takeWhile.lua

@@ -0,0 +1,24 @@
+describe('takeWhile', function()
+  it('produces an error if its parent errors', function()
+    local observable = Rx.Observable.fromValue(''):map(function(x) return x() end)
+    expect(observable.subscribe).to.fail()
+    expect(observable:takeWhile(function() end).subscribe).to.fail()
+  end)
+
+  it('uses the identity function if no predicate is specified', function()
+    local observable = Rx.Observable.fromTable({true, true, false}):takeWhile()
+    expect(observable).to.produce(true, true)
+  end)
+
+  it('stops producing values once the predicate returns false', function()
+    local function isEven(x) return x % 2 == 0 end
+    local observable = Rx.Observable.fromTable({2, 3, 4}, ipairs):takeWhile(isEven)
+    expect(observable).to.produce(2)
+  end)
+
+  it('produces no values if the predicate never returns true', function()
+    local function isEven(x) return x % 2 == 0 end
+    local observable = Rx.Observable.fromTable({1, 3, 5}):takeWhile(isEven)
+    expect(observable).to.produce({})
+  end)
+end)